Ball type CVT with powersplit paths

ABSTRACT

A variable transmission comprises an input shaft; three planetary gear sets; a Ravigneaux gear set; a variator comprising, a first ring assembly, a second ring assembly, a carrier assembly; various arrangements of brakes and clutches; and the output shaft. The variable transmissions comprise a continuously variable mode, an infinitely variable mode, or a combination thereof and can provide an input-coupled powersplit solution function. At least one configuration of the variable transmission comprises a direct drive mode.

CROSS-REFERENCE

This application is filed pursuant to 35 U.S.C. §371 as a United States National Phase Application of International Application No. PCT/US2013/058615, filed Sep. 6, 2013, which application claims the benefit of U.S. Provisional Patent Application No. 61/698,012, filed Sep. 7, 2012 and U.S. Provisional Patent Application No. 61/789,645, filed Mar. 15, 2013, which are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

Automatic and manual transmissions are commonly used on automobile vehicles. Those transmissions are becoming more and more complicated since the engine speed has to be more precisely controlled to limit the fuel consumption and the emissions of cars. This finer control of the engine speed in usual transmissions can only be done by adding more discrete step ratio gears and increasing the overall complexity and cost. Consequently, 6-speed manual transmissions then become more frequently used as are 8 or 9 speed automatic transmissions.

SUMMARY OF THE INVENTION

Provided herein is a variable transmission comprising: an input shaft; three planetary gear sets; a Ravigneaux gear set; a variator comprising, a first ring assembly, a second ring assembly, a carrier assembly; various arrangements of brakes and clutches; and the output shaft.

In some embodiments, the variable transmission comprises a continuously variable mode, an infinitely variable mode or a combination thereof.

In some embodiments the variable transmission can provide an input-coupled powersplit solution function.

In some embodiments, the transition between continuously variable transmission mode and infinitely variable transmission mode is accomplished by releasing or engaging one or more brakes, and/or alternatively releasing or engaging one or more clutches simultaneously.

In some embodiments, the variator is able to continuously change its ratios in both the continuously variable mode and infinitely variable mode to provide the best ratio achievable for the engine to optimize power consumption.

Provided herein is a variable transmission comprising: an input shaft; a first planetary gear set, a second planetary gear set and a third planetary gear set; a variator comprising a first ring assembly, a second ring assembly; a first clutch, a second clutch and a third clutch; and a first brake comprising a first brake member, wherein said input shaft is drivingly engaged with the first ring assembly of the variator, and mechanically coupleable to a first planetary sun of the first planetary gear set using the second clutch; wherein said input shaft is also drivingly engaged with the third sun of the third planetary gear set; wherein the second ring assembly is drivingly engaged with a ring of the third planetary gear set; wherein a first carrier of the first planetary gear set and a second carrier of the second planetary gear set are coupled together, wherein a third carrier of the third planetary gear set is mechanically coupleable to the first carrier of the first planetary and the second carrier of the second planetary through the third clutch; wherein the first brake member is coupled to the ring of the second planetary gear set; and wherein the first ring of the first planetary gear set is mechanically coupled to an output shaft of the variable transmission; wherein the third carrier is mechanically coupled to the second sun of the second planetary gear set; wherein the first sun of the first planetary gear set might be coupled to the first ring of the first planetary gear set with the first clutch.

In some embodiments, the variable transmission comprises two continuously variable modes, an infinitely variable mode and a direct drive mode. In some embodiments, the continuously variable modes of claim 2 comprise a low speed (CVM1) and a high speed (CVM2). In some embodiments, either or both of the continuously variable modes are enabled by blocking rotation of a variator carrier of the variator.

In some embodiments, power from the input shaft passes through the variator and simultaneously passes to a vehicle output. In some embodiments, a slipping clutch is not required between the input shaft and the variable transmission. In some embodiments, a torque converter is not required between the input shaft and the variable transmission

In some embodiments, engaging the second clutch and the first brake results in an infinitely variable mode. In some embodiments, reverse and low positive speeds can be obtained when the input shaft is directly engaged to the first sun of the first planetary gear set by engaging a second clutch.

In some embodiments, engaging the first clutch and the first brake at the second planetary gear set reduces speed of the second ring assembly and allows the first planetary gear set to turn at a 1:1 ratio, thereby engaging a first continuously variable mode (CVM1).

In some embodiments, engaging the first clutch and the third clutch directly drives the variator second ring assembly linked to the first carrier through a 1;1 output ratio from the variator which drives output of the first planetary gear set, thereby engaging a second continuously variable mode (CVM2).

In some embodiments, engaging the second clutch and the first brake engage an infinitely variable mode that allows positive, negative speeds and powered neutral.

In some embodiments, engaging the first clutch and the second clutch bypasses the variator and allows output of the first planetary gear set to turn at a 1:1 ratio with the input shaft, directly engaging a vehicle output, thus engaging a direct-drive mode, In some embodiments, the direct-drive mode is more efficient than either of the two continuously variable modes. In some embodiments, the native efficiency of the variable transmission is increased by using the variator in a power-splitting continuously variable mode.

Provided herein is a variable transmission comprising: an input shaft; a variator comprising a first ring assembly, a second ring assembly; a first planetary gear set, a second planetary gear set and a third planetary gear set; a Ravigneaux gear set; a first clutch; a first brake and a second brake, wherein the input shaft is drivingly engaged with a first sun of the first planetary gear set having the second brake coupled to the ring of this first planetary; wherein the input shaft is drivingly engaged with a second carrier of the second planetary gear set; wherein a second sun of the second planetary gear set is coupled to the first ring assembly of the variator, wherein the second ring assembly is drivingly engaged with a third sun of the third planetary gear, wherein the third ring of the third planetary gear set is fixed to ground, wherein a third carrier of the third planetary gear set is drivingly engaged to a second ring of the second planetary gear set; wherein a second ring of the second planetary gear set is drivingly engaged with the first sun of the Ravigneaux gear set, the Ravigneaux gear set being mechanically coupled to the first brake via its second sun; and wherein a carrier of the Ravigneaux gear set is engaged with a first carrier of the first planetary gear set, and wherein the ring of the Ravigneaux gear set is engaged with a output of the variable transmission; wherein a first clutch engages the first sun of the Ravigneaux gear set to the carrier of the Ravigneaux gear set.

In some embodiments, the first brake holds the second sun of the Ravigneaux gear set.

In some embodiments, the variable transmission comprises a first continuously variable mode, a second continuously variable mode, and an infinitely variable mode. In some embodiments, the first sun of the Ravigneaux gear set is engaged to the third carrier of the third planetary gear set in all of the first continuously variable mode, the second continuously variable mode, and the infinitely variable mode. In some embodiments, the second brake is engaged to hold the first ring of the first planetary gear set, thereby engaging the infinitely variable mode. In some embodiments, the speed of second ring of the Ravigneaux is reduced.

In some embodiments, when the first brake is engaged the second sun is held which results in a first continuously variable mode (CVM1) of operation.

In some embodiments, when the first clutch is engaged, the Ravigneaux gear set is engaged which results in a second continuously variable mode (CVM2) of operation. In some embodiments, in the second continuously variable mode (CVM2) of operation the entire Ravigneaux gear set turns at the same speed, and achieves an efficient 1:1 ratio.

Provided herein is a variable transmission comprising: an input shaft; a variator comprising a first ring assembly, a second ring assembly; a first planetary gear set; a second planetary gear set; a third planetary gear set; a Ravigneaux gear set; a first clutch and a second clutch; and a first brake, a second brake, and a third brake, wherein the input shaft is drivingly engaged with a first sun of the first planetary gear set having the second brake coupled to the ring of this first planetary; wherein the input shaft is drivingly engaged with a second carrier of the second planetary gear set; wherein a second sun of the second planetary gear set is coupled to the first ring assembly of the variator, wherein the second ring assembly is drivingly engaged with a third sun of the third planetary gear set, wherein the third sun and the third carrier of the third planetary gear set are coupled by a second clutch; wherein the third brake is coupled to the ring of the third planetary; wherein the carrier of the third planetary gear set is drivingly engaged with a second ring of the second planetary gear set; wherein the second ring of the second planetary gear set is drivingly engaged with a first sun of the Ravigneaux gear set, and wherein the Ravigneaux gear set is coupled to the first brake by its second sun and wherein a carrier of the Ravigneaux gear set is engaged with a first carrier of the first planetary gear set; wherein a first clutch engages the first sun of the Ravigneaux gear set to the carrier of the Ravigneaux gear set.

In some embodiments, the third brake is configured to release a third ring of the third planetary gear set.

In some embodiments, the variable transmission comprises a first continuously variable mode (CVM1), a second continuously variable mode CVM2), a continuously variable mode (CVM3), and an infinitely variable mode.

In some embodiments, the first sun of the Ravigneaux gear set is engaged to the carrier of the third planetary gear set.

In some embodiments, in the first continuously variable mode (CVM1), or the second continuously variable mode (CVM2), the third brake is engaged.

In some embodiments, in the infinitely variable mode the third brake is engaged.

In some embodiments, in the third continuously variable mode (CVM3), the third brake is disengaged, the first clutch is engaged, and the second clutch is engaged.

In some embodiments, when the third sun and third carrier of the third planetary are coupled by engaging the second clutch, the third planetary gear set to turn at a 1:1 ratio.

In some embodiments, the variator continuously changes its torque ratios in the first continuously variable mode (CVM1), the second continuously variable mode CVM2), the continuously variable mode (CVM3), and the infinitely variable mode to optimize power consumption.

In some embodiments, the variable transmission comprises a traction fluid.

Provided herein is a vehicle driveline comprising a variable transmission described herein or that would be obvious to one of skill in the art upon reading the disclosure herein disposed between an engine and a vehicle output. In some embodiments, the vehicle output comprises a differential and a drive axle. In some embodiments, the vehicle driveline comprises a torsional dampener disposed between the engine and the variable transmission. In some embodiments, the torsional dampener comprises at least one torsional spring.

Provided herein is a method comprising switching between an infinitely variable mode, a continuously variable mode, and a direct drive mode using a variable transmission described herein or that would be obvious to one of skill in the art upon reading the disclosure herein.

Provided herein is a method comprising switching between an infinitely variable mode and two continuously variable modes using a variable transmission described herein or that would be obvious to one of skill in the art upon reading the disclosure herein.

Provided herein is a method comprising switching between an infinitely variable mode and three continuously variable modes using a variable transmission described herein or that would be obvious to one of skill in the art upon reading the disclosure herein.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

FIG. 1 is a side sectional view of a continuously variable planetary (CVP) transmission;

FIG. 2 is a magnified, side sectional view of a ball and ring of the CVP transmission of FIG. 1;

FIG. 3 FIG. 3 is a block diagram of a continuously variable transmission (CVT) used in an automobile;

FIG. 4 is a block diagram of a continuously variable transmission (CVT) according to an embodiment of the present disclosure used in an automobile having both continuously variable modes, a direct drive mode and an infinitely variable mode;

FIG. 5 is a graph of a speed diagram of the CVT of FIG. 4;

FIG. 6 is a block diagram of a continuously variable transmission (CVT) according to another embodiment of the present disclosure having a Ravigneaux gear set used in an automobile having two continuously variable modes and an infinitely variable mode;

FIG. 7 is a graph of a speed diagram of the CVT of FIG. 6;

FIG. 8 is a block diagram of a continuously variable transmission (CVT) according to another embodiment of the present disclosure having a Ravigneaux gear set used in an automobile having three continuously variable modes and an infinitely variable mode; and

FIG. 9 is a graph of a speed diagram of the CVT of FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

Continuously Variable Transmissions or CVTs are of many types: belts with variable pulleys, toroidal, and conical, for non-limiting example. The principle of a CVT is that it enables the engine to run at its most efficient rotation speed by changing steplessly the transmission ratio in function of the speed of the car and the torque demand (throttle position) of the driver. If needed for example when accelerating, the CVT can also shift to the most optimum ratio providing more power. A CVT can change the ratio from the minimum to the maximum ratio without any interruption of the power transmission, as opposed to the opposite of usual transmissions which require an interruption of the power transmission by disengaging to shift from one discrete ratio to engage the next ratio.

A specific use of CVTs is the Infinite Variable Transmission or IVT. Where the CVT is limited at positive speed ratios, the IVT configuration can perform a neutral gear and even reverse steplessly. A CVT can be used as an IVT in some driveline configurations.

Provided herein are configurations based on a ball type CVT, also known as CVP (for constant variable planetary) or a variator, herein. Aspects of an example CVT are described in US20060084549 or AU2011224083A1, incorporated herein by reference in their entirety. The type of CVT used herein is comprised a variator comprising a plurality of variator balls, depending on the application, two discs or annular rings (i.e. a first ring assembly and a second ring assembly) each having an engagement portion that engages the variator balls. The engagement portions may be in a conical or toroidal convex or concave surface contact with the variator balls, as input and output. The variator may include an idler contacting the balls as well as shown on FIG. 1. The variator balls are mounted on axes, themselves held in a cage or carrier allowing changing the ratio by tilting the variator balls' axes. Other types of ball CVTs also exist, like the one produced by Milner but are slightly different. These alternative ball CVTs are additionally contemplated herein. The working principle generally speaking, of a ball-type variator of a CVT is shown in FIG. 2.

The variator itself works with a traction fluid. The lubricant between the ball and the conical rings acts as a solid at high pressure, transferring the power from the first ring assembly, through the variator balls, to the second ring assembly. By tilting the variator balls' axes, the ratio can be changed between input and output. When the axis of each of the variator balls is horizontal the ratio is one, when the axis is tilted the distance between the axis and the contact point change, modifying the overall ratio. All the variator balls' axles are tilted at the same time with a mechanism included in the cage.

In a car, the CVT is used to replace traditional transmission and is located between the engine (ICE or internal combustion engine) and the differential as shown on FIG. 3. A torsional dampener 2 (alternatively called a damper) may be introduced between the engine 100 and the CVT to avoid transferring torque peaks and vibrations that could damage the CVT. In some configurations this dampener can be coupled with a clutch for the starting function.

Embodiment variable transmissions (and resulting drivelines) are shown in FIGS. 4, 6 and 8. Each of these configurations comprises a variator. Such variator comprises a first ring assembly, a second ring assembly, and a carrier assembly disposed therebetween. The carrier assembly includes a plurality of variator balls having tiltable axle shafts as described herein. In some embodiments, the first ring assembly is rotatably disposed in a housing; the first ring assembly comprises a first variator ball engagement surface that is in driving engagement with a plurality of variator balls of the carrier assembly.

A first variator ball engagement surface is formed in a distal end of the first ring assembly. When describing a ring assembly of a tilting ball variator, the term distally refers to the portion of the ring assembly closest to the balls of the variator. In some embodiments, the first variator ball engagement surface is a conical surface or a concave or convex toroidal surface in contact with or slightly spaced apart from each of the variator balls. In some embodiments, the first variator ball engagement surface is in driving engagement with each of the variator balls of the carrier assembly through one of a boundary layer type friction and an elastohydrodynamic film.

The carrier assembly of the variator may be rotatably disposed in the housing and may be drivingly engaged with the first ring assembly. The carrier assembly comprises an annular arrangement of the plurality of tiltable variator balls each having tiltable ball axle shafts. In some embodiments, each of the ball axle shafts is adjusted using a cam style tilting mechanism. In some embodiments, each of the ball axle shafts is adjusted using a split carrier axle skewing mechanism.

As depicted in FIGS. 4, 6, and 8, a second ring assembly is rotatably disposed in the housing. The second ring assembly comprises a second variator ball engagement surface that is in driving engagement with variator balls of the carrier assembly. In some embodiments, the second variator ball engagement surface is formed in a distal end of the second ring assembly. In some embodiments, the second variator ball engagement surface is a conical surface or a concave or convex toroidal surface in contact with or slightly spaced apart from each of the variator balls. In some embodiments, the second variator ball engagement surface is in driving engagement with each of the variator balls of the carrier assembly through one of a boundary layer type friction and an elastohydrodynamic film.

A ball ramp on each side of the variator provides the clamping force necessary to transfer the torque. Ball ramps, indicated in FIGS. 4, 6, and 8 by a circle between a pair of vertical lines, making up a first thrust ring on the first ring assembly and a second thrust ring on the second ring assembly are disposed between components of the variable transmission as shown to generate an amount of axial force necessary for proper operation of the variable transmission (i.e. transfer of torque); however, it is understood that the amount of axial force necessary for proper operation may be generated by a clamping mechanism (not shown) or as a load applied during assembling of the variable transmission. Thus, as depicted in FIGS. 4, 6, and 8, a ball ramp on each side of the variator provides the clamping force necessary to transfer the torque in this embodiment.

Provided herein is a series of configurations for a variable transmission comprising: an input shaft; three planetary gear sets; a variator comprising, a first ring assembly, a second ring assembly, a carrier assembly; at least one of a brake or a clutch; and the output shaft. Some of the configurations provided herein may further comprise a Ravigneaux gear set.

In some embodiments, the variable transmission comprises a continuously variable mode, an infinitely variable mode or a combination thereof. In some embodiments, the variable transmission comprises a direct drive mode.

In some embodiments the variable transmission provides an input-coupled powersplit solution function.

In some embodiments, the transition between continuously variable transmission mode and infinitely variable transmission mode is accomplished by releasing or engaging one or more brakes, and/or alternatively releasing or engaging one or more clutches simultaneously.

In some embodiments, the variator is able to continuously change its ratios in both the continuously variable mode and infinitely variable mode to provide the best ratio achievable for the engine to optimize power consumption.

Provided herein is a variable transmission comprising: an input shaft; a first planetary gear set, a second planetary gear set and a third planetary gear set; a variator comprising a first ring assembly, a second ring assembly; a first clutch, a second clutch and a third clutch; and a first brake comprising a first brake member, wherein said input shaft is drivingly engaged with the first ring assembly of the variator, and mechanically coupleable to a first planetary sun of the first planetary gear set using the second clutch; wherein said input shaft is also drivingly engaged with a third sun of the third planetary gear set; wherein the second ring assembly is drivingly engaged with a ring of the third planetary gear set; wherein a first carrier of the first planetary gear set and a second carrier of the second planetary gear set are coupled together, wherein a third carrier of the third planetary gear set is mechanically coupleable to the first carrier of and the second carrier through the third clutch; wherein the first brake member is coupled a second ring of the second planetary gear; and wherein the first ring of the first planetary gear set is mechanically coupled to the output of the transmission; wherein the third carrier is mechanically coupled to the second sun of the second planetary gear set; wherein the first sun of the first planetary gear set might be coupled to the first ring of the first planetary gear set with the first clutch.

In some embodiments, the variable transmission comprises two continuously variable modes and an infinitely variable mode and a direct drive mode. In some embodiments, the continuously variable modes of claim 2 comprise a low speed (CVM1) and a high speed (CVM2). In some embodiments, either or both of the continuously variable modes are enabled by blocking rotation of a variator carrier of the variator.

In some embodiments, power from the input shaft passes through the variator and simultaneously passes to a vehicle output. In some embodiments, wherein a slipping clutch is not required between the input shaft and the variable transmission. In some embodiments, wherein a torque converter is not required between the input shaft and the variable transmission

In some embodiments, engaging the second clutch and the first brake results in an infinitely variable mode. In some embodiments, reverse and low positive speeds can be obtained when the input shaft is directly engaged to the first sun of the first planetary gear set by engaging a second clutch.

In some embodiments, engaging the first clutch and the first brake at the second planetary gear set reduces speed of the second ring assembly and allows the first planetary gear set to turn at a 1:1 ratio, thereby engaging a first continuously variable mode (CVM1).

In some embodiments, engaging the first clutch and the third clutch directly drives the variator second ring assembly linked to the first carrier of the first planetary gear set through a 1:1 output ratio from the variator which drives output of the first planetary gear set, thereby engaging a second continuously variable mode (CVM2).

In some embodiments, engaging the first clutch and the third clutch directly links the output of the first planetary gear set (at the first ring) to the third carrier in a 1:1 output ratio

In some embodiments, engaging the second clutch and the first brake engage an infinitely variable mode that allows positive, negative speeds and powered neutral. (IVP).

In some embodiments, engaging the first clutch and the second clutch bypasses the variator and allows output of the first planetary gear set to turn at a 1:1 ratio with the input shaft, directly engaging a vehicle output, thus engaging a direct drive mode, In some embodiments, the direct drive mode is more efficient than either of the two continuously variable modes. In some embodiments, wherein native efficiency of the variable transmission is increased by using the variator in a power-splitting continuously variable mode.

Provided herein is a variable transmission comprising: an input shaft; a variator comprising a first ring assembly, a second ring assembly; a first planetary gear set, a second planetary gear set and a third planetary gear set; a Ravigneaux gear set; a first clutch; and a first brake and a second brake, wherein the input shaft is drivingly engaged with a first sun of the first planetary gear set having the second brake coupled to the ring of the first planetary gear set; wherein the input shaft is drivingly engaged with a second carrier of the second planetary gear set; wherein a second sun of the second planetary gear set is coupled to the first ring assembly of the variator, wherein the second ring assembly is drivingly engaged with a third sun of the third planetary gear set, the third ring of the third planetary gear set being fixed to ground wherein a third carrier of the third planetary gear set is drivingly engaged to a second ring of the second planetary gear set; wherein a second ring of the second planetary is drivingly engaged with the first sun of the Ravigneaux gear set, the Ravigneaux gear set being mechanically coupled to the first brake by its second sun; and wherein a carrier of the Ravigneaux gear set is engaged with the first carrier of the first planetary gearset; and wherein the ring of the Ravigneaux gear set is coupled to the variable transmission output; and wherein a first clutch engages the first sun of the Ravigneaux gear set to the carrier of the Ravigneaux gear set.

In some embodiments, the first brake holds the second sun of the Ravigneaux gear set. In some embodiments, the second brake holds the first ring of the first planetary gear set. In some embodiments, the ring of the Ravigneaux gear set is linked to a first carrier of the first planetary gear set.

In some embodiments, the variable transmission comprises a first continuously variable mode, a second continuously variable mode, and an infinitely variable mode. In some embodiments, first sun of the Ravigneaux gear set is engaged in all of the first continuously variable mode, the second continuously variable mode, and the infinitely variable mode to the carrier of the third planetary gear set.

In some embodiments, the second brake is engaged to hold the first ring of the first planetary gear set, thereby engaging the infinitely variable mode. In some embodiments, the speed of second ring of the Ravigneaux is reduced.

In some embodiments, when the first brake is engaged the second sun is held which results in a first continuously variable mode (CVM1) of operation.

In some embodiments, when the first clutch is engaged, the Ravigneaux gear set is engaged which results in a second continuously variable mode (CVM2) of operation. In some embodiments, in the second continuously variable mode (CVM2) of operation the entire Ravigneaux gear set turns at the same speed, and achieves an efficient 1:1 ratio.

Provided herein is a variable transmission comprising: an input shaft; a variator comprising a first ring assembly, a second ring assembly; a first planetary gear set, a second planetary gear set and a third planetary gear set; a Ravigneaux gear set; a first clutch and a second clutch; and a first brake, a second brake, and a third brake, wherein the input shaft is drivingly engaged with a first sun of the first planetary gear set having the second brake coupled to the ring of this first planetary gear set; wherein the input shaft is drivingly engaged with a second carrier of the second planetary gear set; wherein a second sun of the second planetary gear set is coupled to the first ring assembly of the variator, wherein the second ring assembly is drivingly engaged with a third sun of the third planetary gear set, wherein the third sun and the third carrier of the third planetary gear set are coupled by a second clutch; wherein the third brake is coupled to the third ring of the third planetary gear set; wherein the carrier of the third planetary gear set is drivingly engaged with a second ring of the second planetary gear set; wherein the second ring of the second planetary gear set is drivingly engaged with a first sun of the Ravigneaux gear set, the Ravigneaux gear set being coupled to the first brake by its second sun and wherein a carrier of the Ravigneaux gear set is engaged a first carrier of the first planetary gearset; wherein a ring of the Ravigneaux gear set is coupled to the variable transmission output; and wherein a first clutch engages the first sun of the Ravigneaux gear set to the carrier of the Ravigneaux gear set.

In some embodiments, the third brake is configured to release a third ring of the third planetary gear set.

In some embodiments, the variable transmission comprises a first continuously variable mode (CVM1), a second continuously variable mode (CVM2), a continuously variable mode (CVM3), and an infinitely variable mode.

In some embodiments, the first sun of the Ravigneaux gear set is engaged to the carrier of the third planetary gear set in each of the first continuously variable mode (CVM1), the second continuously variable mode (CVM2), the continuously variable mode (CVM3), and the infinitely variable mode.

In some embodiments, in the first continuously variable mode (CVM1), or the second continuously variable mode (CVM2), the third brake is engaged.

In some embodiments, in the infinitely variable mode the third brake is engaged.

In some embodiments, in the third continuously variable mode (CVM3), the third brake is disengaged, the first clutch is engaged, and the second clutch is engaged.

In some embodiments, when the third sun of the third planetary gear set and third carrier of the third planetary gear set are coupled, the third planetary gear set is configured to turn at a 1:1 ratio.

In some embodiments, the variator continuously changes its torque ratios in the first continuously variable mode (CVM1), the second continuously variable mode CVM2), the continuously variable mode (CVM3), and the infinitely variable mode to optimize power consumption.

In some embodiments, the variable transmission comprises a traction fluid.

Provided herein is a vehicle driveline comprising a variable transmission described herein or that would be obvious to one of skill in the art upon reading the disclosure herein disposed between an engine and a vehicle output. In some embodiments, the vehicle output comprises a differential and a drive axle. In some embodiments, the vehicle driveline comprises a torsional dampener disposed between the engine and the variable transmission. In some embodiments, the torsional dampener comprises at least one torsional spring.

Provided herein is a method comprising switching between an infinitely variable mode and a continuously variable mode using a variable transmission described herein or that would be obvious to one of skill in the art upon reading the disclosure herein.

Provided herein is a method comprising switching between an infinitely variable mode and two continuously variable modes using a variable transmission described herein or that would be obvious to one of skill in the art upon reading the disclosure herein.

Provided herein is a method comprising switching between an infinitely variable mode and three continuously variable modes using a variable transmission described herein or that would be obvious to one of skill in the art upon reading the disclosure herein.

Provided herein is a vehicle comprising a variable transmission described herein or that would be obvious to one of skill in the art upon reading the disclosure herein disposed between an engine and a vehicle output.

EXAMPLE 1

The embodiment of FIG. 4 depicts a variable transmission 3 a comprising: a variator 8 a comprising a first ring assembly 81 ra, a second ring assembly 82 ra, with variator balls 8 ba drivingly engaged therebetween, typically mounted on a carrier (not shown); a first planetary gear set 5 a comprising a first sun gear 5 sa (sometimes simply referred to as “first sun”), a first ring gear 5 ra (sometimes simply referred to as “first ring”), a first planet carrier 5 ca (also referred to as “first carrier”), and a first set of planets gears 5 pa; a second planetary gear set 6 a comprising a second sun gear 6 sa (sometimes simply referred to as “second sun”), a second ring gear 6 ra (sometimes simply referred to as “second ring”), a second planet carrier 6 ca (also referred to as “second carrier”), and a second set of planets gears 6 pa, a third planetary gear set 7 a comprising a third sun gear 7 sa (sometimes simply referred to as “third sun”), a third ring gear 7 ra (sometimes simply referred to as “third ring”), a third planet carrier 7 ca (also referred to as “third carrier”), and a third set of planets gears 7 pa; a first clutch 10 a; a second clutch 11 a; a third clutch 12 a; a first brake 13 a; input shaft 1 a; and output 50 a.

The embodiment of FIG. 4 is an input-coupled powersplit solution, meaning that a part of the power will pass through the variator while the remaining power will pass to the output through a mechanical path with higher efficiency. This power-splitting permits a relatively small variator and an increase to the native efficiency of the transmission. The central part of the configuration is the variator 8 a described previously in the document. A ball ramp on each side of the variator provides the clamping force necessary to transfer the torque. The variator is only used in continuously variable mode by blocking rotation of the variator carrier of the variator.

This configuration has an infinitely variable mode to provide a standstill, reversed and starting function; two continuously variable modes, one for low speeds and one for high speeds; and a fuel efficient direct drive mode. No starting device like a slipping clutch or torque converter is required, since the IVP mode takes care of the starting function.

In the embodiment depicted in FIG. 4 a motor 100 such as an internal combustion engine (ICE) is coupled to the variator first ring assembly 81 ra via input shaft 1 a and can be linked to the first sun 5 sa of the first planetary gear set 5 a with second clutch 11 a. The ICE is also linked to the sun 7 sa of third planetary gear set 7 a. The variator second ring assembly 82 ra is coupled to the ring 7 ra of third planetary gear set 7 a. The carrier 7 ca of third planetary gear set 7 a can be directly linked to the carriers 5 ca and 6 ca of first planetary gear set 5 a and second planetary gear set 6 a with the use of the third clutch 12 a, or the carrier 7 ca can be reduced in speed by applying the first brake 13 a to the ring 6 ra of the second planetary gear set 6 a. The ring 5 ra of first planetary gear set 5 a is coupled to the output 50 a of the variable transmission 3 a and goes directly to the differential 4. By engaging the first clutch 10 a, the first planetary gear set 5 a turns in an efficient 1:1 ratio. The carrier 7 ca of third planetary gear set 7 a is directly linked to the sun 6 sa of second planetary gear set 6 a.

As shown in FIG. 5, the three horizontal axes 501, 502, and 503 represent respectively, from the bottom to the top, the third sun 7 sa rotation speed, the first carrier 5 ca rotation speed and the first ring 5 ra rotation speed. An example Motor 100 speed is shown at point 505 for a reference. The output speed range of the variable transmission in IVP mode is represented by the segment 520 between speeds 508 and 509 shown corresponding to the first ring 5 ra speed. Speed 510 is shown which corresponds to the carrier 5 ca speed when the IVT mode is operating as a powered neutral. The output speed range of the variable transmission 3 a in CVM1 is represented by the region 521 between speeds 506 and 507 shown on axis 503. The output speed range for variable transmission 3 a in CVM2 is shown by the segment 522 between speeds 511 and 512. Note that for CVM1 and CVM2 the output speeds are identical to the corresponding speeds on axis 502 (shown connected by vertical arrows). This is because in such modes the first ring 5 ra and first carrier 5 ca are rotatably fixed to each other due to the engagement of the first clutch 10 a. In direct drive the output of the variable transmission 3 a matches the engine speed 505 at output speed 515.

In IVP mode, second clutch 11 a and first brake 13 a are closed (engaged). The sun 5 sa of the first planetary gear set 5 a turns at motor 100 speed and the output speed of the variator is reduced at the second planetary gear set 6 a. This is then linked to the first carrier 5 ca of the first planetary gear set 5 a. At the first ring 5 ra of the first planetary gear set 5 a, (output to differential) reversed and low positive speeds (IVP) when the ICE is coupled to the first sun 5 sa of the first planetary gear set 5 a by applying the second clutch 11 a. In this mode, powersplitting occurs two times. A part of the input power goes to the first sun 5 sa of the first planetary gear set 5 a and part of it goes to the variator 8 a. The latter then splits the power again, in a part going to the variator first ring assembly 81 ra and a part going to the third sun 7 sa of the third planetary gear set 7 a.

In CVM1 mode, the first clutch 10 a and first brake 13 a are applied. The output speed of the variator is reduced at the second planetary gear set 6 a. This is then linked to the first ring 5 ra (output to the differential) by applying the first clutch 10 a, allowing the first planetary gear set 5 a to turn at a 1:1 ratio. In this mode there is powersplitting.

In CVM2 mode, the first clutch 10 a and third clutch 12 a are applied. The output speed of the variator is directly linked to the first carrier 5 ca of the first planetary 5 a. This is then linked to the output to the differential by applying the first clutch 10, allowing the first planetary gear set 5 a to turn at a 1:1 ratio. In this mode there is powersplitting.

Direct drive mode provides an efficient way for high-speed driving, like on the highway. It is obtained by engaging first clutch 10 a and second clutch 11 a, therefore bypassing the CVP and allowing the output planetary (first planetary gear set 5 a) to turn at a 1:1 ratio. The motor 100 is then directly linked to the differential without powersplitting.

This device is able to change continuously its ratio to provide the best ratio achievable for the engine in function of the objectives of consumption of power. In a manual or automatic transmission, only some predetermined and discrete ratios are available and an interruption of the power transmission is needed to shift of ratio. The only interruptions of power in this device are the modes shifting. Other advantages of this configuration are that a small variator can be chosen; spread is larger to a traditional gearbox and the native efficiency of the transmission is increased by using the variator in a powersplit device, therefore letting a part of the power passing through a more efficient mechanical path. This particular configuration has an extra advantage by having an efficient direct drive mode for cruising speeds, bypassing the less efficient variator.

EXAMPLE 2

The embodiment of FIG. 6 depicts a variable transmission 3 b comprising: a variator 8 b comprising a first ring assembly 81 rb, a second ring assembly 82 rb, with variator balls 8 bb drivingly engaged therebetween, typically mounted on a carrier (not shown); a first planetary gear set 5 b comprising a first sun gear 5 sb (sometimes simply referred to as “first sun”), a first ring gear 5 rb (sometimes simply referred to as “first ring”), a first planet carrier 5 cb (also referred to as “first carrier”), and a first set of planets gears 5 pb; a second planetary gear set 6 b comprising a second sun gear 6 sb (sometimes simply referred to as “second sun”), a second ring gear 6 rb (sometimes simply referred to as “second ring”), a second planet carrier 6 cb (also referred to as “second carrier”), and a second set of planets gears 6 pb, a third planetary gear set 7 b comprising a third sun gear 7 sb (sometimes simply referred to as “third sun”), a third ring gear 7 rb (sometimes simply referred to as “third ring”), a third planet carrier 7 cb (also referred to as “third carrier”), and a third set of planets gears 7 pb; a Ravigneaux gear set 9 b comprising a first Ravigneaux sun 91 sb, a second Ravigneaux sun 92 sb, a planetary carrier 9 cb, a ring gear 9 rb, a set of inner planet gears 93 pb, and a set of outer planet gears 94 pb. a first clutch 10 b; a first brake 13 b; a second brake 14 b; input shaft 1 b; and output 50 b.

The embodiment depicted in FIG. 6 is an input and output coupled powersplit solution, meaning that the powersplitting occurs two times (only in infinitely variable mode, in the other modes it is an output-coupled system only). Powersplitting occurs in infinitely variable mode the first time at the first planetary gear set 5 b. Part of the power flows to the Ravigneaux gear set 9 b and a part flows to the second planetary gear set 6 b. Powersplitting occurs at the second planetary gear set 6 b. Part of the power flows through the less efficient variator 8 b and a part flows through a mechanical path to the third planetary gear set 7 b. This power splitting allows the embodiment have a relatively small variator and to increase the native efficiency of the transmission. The central part of that configuration is the variator described previously in the document. A ball ramp on each side of the variator provides the clamping force necessary to transfer the torque. The variator is also only used in continuously variable mode by always blocking rotation of the variator carrier of the variator.

This configuration has an infinitely variable mode to provide a standstill, reversed and starting function and two continuously variable modes, one for low speeds and one for high speeds. No starting device like a slipping clutch or torque converter is required, since the infinitely variable mode takes care of the starting function.

The motor 100, such as an ICE, is coupled to the first sun 5 sb of the first planetary gear set 5 b and to the second carrier 6 cb of the second planetary gear set 6 b. The second sun 6 sb of the second planetary gear set 6 b is coupled to the variator first ring assembly 81 ra. The variator second ring assembly 82 rb is then coupled to the third sun 7 sb of the third planetary gear set 7 b, the third planetary gear set being linked to the ground at its ring 7 rb and to the second ring 6 rb of the second planetary gear set 6 b by its carrier. The second ring 7 rb of the second planetary gear set 7 b is coupled to the first sun 91 sb of the Ravigneaux gear set 9 b and can be coupled to the carrier 9 cb of the Ravigneaux 9 b by engaging a first clutch 10 b. By engaging that first clutch 10 b, the Ravigneaux 9 b turns in an efficient 1:1 ratio. The carrier 9 cb of the Ravigneaux 9 b is the coupled to the first carrier 6 cb of the first planetary gear box 6 b. The ring 9 rb of the Ravigneaux 9 b is coupled to the variable transmission output 50 b which is coupled directly to the final drive and differential (i.e. the vehicle output). Two brakes, including first brake 13 b and second brake 14 b allow either holding the second Ravigneaux sun 92 sb of the Ravigneaux 9 b (by first brake 13 b) or either the first ring 5 rb of the first planetary 5 b (by second brake 14 b).

FIG. 7 shows the speed diagram of the configuration of FIG. 6 (Example 2). As shown in FIG. 7, the four horizontal axes 701-704 represent respectively, from the bottom to the top, the first Ravigneaux sun 91 sb rotation speed, the Ravigneaux carrier 9 cb rotation speed, the second Ravigneaux ring 9 rb rotation speed, and the second Ravigneaux sun 92 sb rotation speed. The variable transmission output in infinitely variable mode spans the speeds bounded by speeds 709 and 710 (at the ring 9 rb). The variable transmission output speeds in CVM1 span the speeds bounded by 710 and 711, while the variable transmission output speeds in CVM2 span the speeds bounded by 711 and 712. As shown, these speed ranges form a continuous overall output range. However this is dependent upon the gear ratios chosen for the various elements of the variable transmission. The speed ratios may be chosen such that each mode's output ranges may or may not overlap. The output speed is represented by the bolded horizontal line on the carrier rotation speed line starting from the intersection of the first dotted line and the bolded horizontal line, and ending on the intersection of the second vertical dotted line and the bolded horizontal line. The output speed powersplit is the speed at the second ring assembly 82 rb of the variator 8 b and is bounded by speeds 707 and 706 shown on axis 701. The motor speed 705 is shown for reference as well.

The first Ravigneaux sun 91 sb is coupled to the output of the powersplit in the three modes. That powersplit output speed is shown on the first Ravigneaux sun 91 sb axis.

The infinitely variable mode is activated by engaging the second brake 14 b to hold the first ring 5 rb of the first planetary gear set 5 b. The Ravigneaux carrier 9 cb of the Ravigneaux 9 b being coupled to the first carrier 5 cb of the first planetary gear set 5 b, its speed is reduced to the point 708 shown on the axis 702. As the ring 9 rb is the output of the variable transmission, the output speed achievable can be observed on the ring axis 703 of the speed diagram.

The first continuously variable mode (CVM1) is activated by holding the second Ravigneaux sun 92 sb with the first brake 13 b. The speed achievable can be observed in the speed diagram between speeds 710 and 711.

The second continuously variable mode (CVM2) is activated when the first clutch 10 b is engaged, doing this, the whole Ravigneaux gear set 9 b is turning at the same speed and achieving an efficient 1:1 ratio.

EXAMPLE 3

The embodiment of FIG. 8 demonstrates and comprises that a mode can be added to that concept of Example 2 by adding one clutch and one brake. The embodiment of FIG. 8 depicts a variable transmission 3 c comprising: a variator 8 c comprising a first ring assembly 81 rc, a second ring assembly 82 rc, with variator balls 8 bc drivingly engaged therebetween, typically mounted on a carrier (not shown); a first planetary gear set 5 c comprising a first sun gear 5 sc (sometimes simply referred to as “first sun”), a first ring gear 5 rc (sometimes simply referred to as “first ring”), a first planet carrier 5 cc (also referred to as “first carrier”), and a first set of planets gears 5 pc; a second planetary gear set 6 c comprising a second sun gear 6 sc (sometimes simply referred to as “second sun”), a second ring gear 6 rc (sometimes simply referred to as “second ring”), a second planet carrier 6 cc (also referred to as “second carrier”), and a second set of planets gears 6 pc, a third planetary gear set 7 c comprising a third sun gear 7 sc (sometimes simply referred to as “third sun”), a third ring gear 7 rc (sometimes simply referred to as “third ring”), a third planet carrier 7 cc (also referred to as “third carrier”), and a third set of planets gears 7 pc; a Ravigneaux gear set 9 c comprising a first Ravigneaux sun 91 sc, a second Ravigneaux sun 92 sc, a planetary carrier 9 cc, a ring gear 9 rc, a set of inner planet gears 93 pc, and a set of outer planet gears 94 pc; a first clutch 10 c; a second clutch 11 c; a first brake 13 c; and a second brake 14 c; a third brake 15 c; input shaft 1 c; and output 50 c.

The additional clutch 11 c is placed between the variator second ring assembly 82 rc and the third planetary gear set 7 c carrier 7 cc (still coupled to the second planetary ring 6 rc) and the third brake 15 c is allowing to release the third ring 7 rc of the third planetary gear set 7 c.

FIG. 9 shows the speed diagram of the configuration of FIG. 8 (Example 3). As shown in FIG. 9, the four horizontal axes 901-904 represent respectively, from the bottom to the top, the first Ravigneaux sun 91 sc rotation speed, the second Ravigneaux carrier 9 cc rotation speed, the ring 9 rc rotation speed and the second Ravigneaux sun 92 sc rotation speed. In IVP mode the variable transmission output speed at the ring 9 rc is shown between speed points 909 and 910. In CVM1 the variable transmission output speeds are shown between speed points 910 and 911. In CVM2 the variable transmission outputs speeds lie between speed points 911 and 912. In CVM3 the variable transmission output speeds lie between speed points 912-914. The speed ranges just enumerated depend upon the gear ratios of the various components of the variable transmission. The gear ratios may be chosen such that output speed ranges of the various modes form a continuous range or a discontinuous range. The speeds 907, 906, and 913 match the speeds 911, 912, and 913 in CVM2 and CVM3 because due to the engagement of the first clutch the sun 91 sc and the ring 9 rc are rotatably fixed to each other. The speed range 907-913 may also correspond to the speed at the second ring assembly 82 rc of the variator 8 c. An example motor speed 905 is shown on axis 901 for reference.

The additional brake 15 c is engaged in the three former modes (IVP, CVM1, CVM2) while the additional clutch is released 11 c.

To engage CVM3 mode, the third brake 15 c is opened and the second clutch 11 c is engaged, as well as the first clutch 10 c. The sun 7 sc and the third carrier 7 cc of the third planetary gear set 7 c are then coupled, making the third planetary gear set turn at an efficient 1:1 ratio.

The variable transmission of embodiment of FIG. 8 is able to change continuously its ratio to provide the best ratio achievable for the engine in function of the objectives of consumption of power. In a manual or automatic transmission, only some predetermined and discrete ratios are available and an interruption of the power transmission is needed to shift of ratio. The only interruptions of power in the variable transmission of embodiment of FIG. 8 are the modes shifting. Other advantages of this configuration are that a small variator can be chosen; spread is comparable (re: Example 2) or larger (re: Example 3) compared to a traditional gearbox and the native efficiency of the transmission is increased by using the variator in a powersplit device, therefore letting a part of the power passing through a more efficient mechanical path. This is especially true for the infinitely variable mode, where powersplitting occurs two times.

Embodiments of the variable transmission described herein or that would be obvious to one of skill in the art upon reading the disclosure herein are contemplated for use in a variety of vehicle drivelines. For non-limiting example, the variable transmissions disclosed herein may be used in bicycles, mopeds, scooters, motorcycles, automobiles, electric automobiles, trucks, sport utility vehicles (SUV's), lawn mowers, tractors, harvesters, agricultural machinery, all terrain vehicles (ATV's), jet skis, personal watercraft vehicles, airplanes, trains, helicopters, buses, forklifts, golf carts, motorships, steam powered ships, submarines, space craft, or other vehicles that employ a transmission. Provided herein is a vehicle comprising a variable transmission described herein or that would be obvious to one of skill in the art upon reading the disclosure herein disposed between an engine and a vehicle output.

While the figures and description herein are directed to ball-type variators (CVTs), alternate embodiments are contemplated another version of a variator (CVT), such as a Variable-diameter pulley (VDP) or Reeves drive, a toroidal or roller-based CVT (Extroid CVT), a Magnetic CVT or mCVT, Ratcheting CVT, Hydrostatic CVTs, Naudic Incremental CVT (iCVT), Cone CVTs, Radial roller CVT, Planetary CVT, or any other version CVT.

While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby. 

What is claimed is:
 1. A variable transmission comprising: an input shaft; a first planetary gear set, a second planetary gear set and a third planetary gear set; a variator comprising a first ring assembly, a second ring assembly; a first clutch, a second clutch and a third clutch; and a first brake comprising a first brake member, wherein said input shaft is drivingly engaged with the first ring assembly of the variator, and mechanically coupleable to a first planetary sun of the first planetary gear set using the second clutch; wherein said input shaft is also drivingly engaged with the third sun of the third planetary gear set; wherein the second ring assembly is drivingly engaged with a ring of the third planetary gear set; wherein a first carrier of the first planetary gear set and a second carrier of the second planetary gear set are coupled together, wherein a third carrier of the third planetary gear set is mechanically coupleable to the first carrier of the first planetary gear set and the second carrier of the second planetary gear set through the third clutch; wherein the first brake member is coupled to the ring of the second planetary gear set; and wherein the first ring of the first planetary gear set is mechanically coupled to the output of the transmission; wherein the third carrier is mechanically coupled to the second sun of the second planetary gear set; wherein the first sun of the first planetary gear set might be coupled to the first ring of the first planetary gear set with the first clutch.
 2. The variable transmission of claim 1, comprising two continuously variable modes and an infinitely variable mode and a direct drive mode.
 3. The variable transmission of claim 2, wherein the continuously variable modes of claim 2 comprise a low speed (CVM1) and a high speed (CVM2).
 4. The variable transmission of claim 2, wherein either or both of the continuously variable modes and infinitely variable modes are enabled by blocking rotation of a variator carrier of the variator.
 5. The variable transmission of claim 2, wherein engaging the first clutch and the first brake at the second planetary gear set reduces speed of the second ring assembly and allows the first planetary gear set to turn at a 1:1 ratio, thereby engaging a first of the two continuously variable modes (CVM1).
 6. The variable transmission of claim 2, wherein engaging the first clutch and the third clutch drives the output speed of the variator second ring assembly through the carrier of the first planetary gear set causing the first planetary gear set to turn at a 1:1 output ratio to the differential, thereby engaging a second continuously variable mode (CVM2) with powersplitting.
 7. The variable transmission of claim 2, wherein engaging the first clutch and the second clutch bypasses the variator and allows output of the first planetary gear set to turn at a 1:1 ratio with the input shaft, directly engaging a vehicle output, thus engaging a direct drive mode.
 8. The variable transmission of claim 2, wherein engaging the second clutch and the first brake engage a infinitely variable mode that allows positive speeds, negative speeds and powered neutral (IVP).
 9. The variable transmission of claim 1, wherein power from the input shaft passes through the variator and simultaneously passes to a vehicle output.
 10. The variable transmission of claim 1, wherein engaging the second clutch and the first brake results in an infinitely variable mode.
 11. The variable transmission of claim 10, wherein reverse and low positive speeds can be obtained when the input shaft is directly engaged to the first sun of the first planetary gear set.
 12. The variable transmission of claim 1, comprising a traction fluid.
 13. The variable transmission of claim 1, disposed between an engine and a vehicle output, thereby forming a vehicle driveline.
 14. A variable transmission comprising: an input shaft; a variator comprising a first ring assembly, a second ring assembly; a first planetary gear set, a second planetary gear set and a third planetary gear set; a Ravigneaux gear set; a first clutch; and a first brake and a second brake, wherein the input shaft is drivingly engaged with a first sun of the first planetary gear set having the second brake coupled to the ring of this first planetary gear set; wherein the input shaft is drivingly engaged with a second carrier of the second planetary gear set; wherein a second sun of the second planetary gear set is coupled to the first ring assembly of the variator, wherein the second ring assembly is drivingly engaged with a third sun of the third planetary gear set which is fixed to ground by its ring, wherein a third carrier of the third planetary gear set is drivingly engaged to a second ring of the second planetary gear set; wherein a second ring of the second planetary is drivingly engaged with the first sun of the Ravigneaux gear set which is mechanically coupled to the first brake by its second sun; and wherein a ring of the Ravigneaux gear set is engaged with a vehicle output; and wherein a first clutch engages the first sun of the Ravigneaux gear set to a carrier of the Ravigneaux gear set.
 15. The variable transmission of claim 14, wherein the first brake holds the second sun of the Ravigneaux gear set.
 16. The variable transmission of claim 14, wherein the second brake holds the ring gear of the first planetary gear set.
 17. The variable transmission of claim 14, wherein the carrier of the Ravigneaux gear set is linked to a first carrier of the first planetary gear set.
 18. The variable transmission of claim 14, comprising a first continuously variable mode, a second continuously variable mode, and an infinitely variable mode.
 19. The variable transmission of claim 18, wherein the first sun of the Ravigneaux gear set is engaged in all of the first continuously variable mode, the second continuously variable mode, and the infinitely variable mode.
 20. The variable transmission of claim 14, wherein the second brake is engaged to hold the first ring of the first planetary gear set, thereby engaging the infinitely variable mode.
 21. The variable transmission of claim 20, wherein the speed of second ring of the Ravigneaux is reduced.
 22. The variable transmission of claim 14, wherein when the first brake is engaged the second sun is held which results in a first continuously variable mode (CVM1) of operation.
 23. The variable transmission of claim 14, wherein when the first clutch is engaged, the Ravigneaux gear set is engaged which results in a second continuously variable mode (CVM2) of operation.
 24. The variable transmission of claim 23, wherein in the second continuously variable mode (CVM2) of operation the entire Ravigneaux gear set turns at the same speed, and achieves an efficient 1:1 ratio.
 25. The variable transmission of claim 14, further comprising a second clutch and a third brake, the second clutch operably coupled to the third planetary gear set, the third brake operably coupled to the third planetary gear set.
 26. The variable transmission of claim 14, comprising a traction fluid.
 27. The variable transmission of claim 14, disposed between an engine and a vehicle output, thereby forming a vehicle driveline. 